Gyroid-structured SiOC composite with excellent broadband microwave absorption and load-bearing performance

Designing materials with both structural load-bearing capacity and broadband electromagnetic (EM) wave absorption properties remains a significant challenge. In this work, SiOC/SiC/SiO₂ composite with gyroid structures were prepared through digital light processing (DLP) 3D printing, polymer-derived ceramics (PDCs), chemical vapor infiltration (CVI), and oxidation technologies. The incorporation of the CVI SiC phase effectively increases the dissipation capability, while the synergistic interaction between the gyroid structure and SiO₂ phase significantly improves impedance matching performance. The SiOC/SiC/SiO₂ composite achieved a minimum reflection loss (RL_min) of −62.2 dB at 4.3 mm, and the effective absorption bandwidth (EAB) covered the X-band, with a thickness range of 4.1 mm–4.65 mm. The CST simulation results explain the broadband and low-frequency absorption characteristics, with an EAB of 8.4 GHz (9.6–18 GHz) and an RL_min of −21.5 dB at 5 GHz. The excellent EM wave attenuation performance is associated primarily with polarization loss, conduction loss, the gyroid structure's enhancement of multiple reflections and scattering of EM waves, and the resonance effect between the structural units. The SiOC/SiC/SiO₂ composite also demonstrated strong mechanical properties, with a maximum compressive failure strength of 31.6 MPa in the height direction. This work opens novel prospects for the development of multifunctional structural wave-absorbing materials suitable for broadband microwave absorption and load-bearing properties.